Sister-in-Law!

Aihime Utsumi, a first-year high school student, experiences an unexpected shift in her relaxed daily routine when a strikingly attractive girl unexpectedly arrives at her home. Identified as her sister-in-law, the girl's sudden presence disrupts Aihime's peaceful life. With the rest of the family absent, Aihime and the new arrival are left to share the household, adjusting to their unusual living arrangement.